Instance Mirror Toggle
From Nevercenter 3D Modeling Wiki
Default Shortcut: Shift + I
Menu Path: Modify > Mirroring > Instance Mirror Toggle
The Instance Mirror command is an alternative to Silo's Symmetry commands which is less powerful but also simpler, faster, and in some cases more reliable. The general workflow is to delete half of a model which you want to be symmetrical and then use this command to replace the missing half with a mirrored instance of the remaining model. The instanced half will reflect all changes made to the original half instantly, and can be thought of as a preview of what your final, mirrored model will look like. When finished, you can use Mirror Geometry to create actual geometry for the missing half.
Mirror From Axis
- This is the axis along which you would like to mirror. (For example, choosing the X axis would mirror across the local YZ plane.) If the instance mirror appears strange or does not show up, you may be using the wrong axis. Note that the local axis is used, which means that the object can be moved or rotated in object mode and the instance mirror will update properly.
- Vertices along the central seam between the object and the instance can be held together as if it were a unified object. This tolerance determines how far from the center vertices can be and still be treated as if they were on the center seam. If vertices are accidentally getting pulled into the center seam, you will want to use a smaller tolerance.
- The Instance Mirror, unlike a regular Instance, cannot be selected or edited in any way.